Дисертації з теми "Power-to-fuel"
Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Power-to-fuel.
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Power-to-fuel".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Moore, Christopher Wayne. "Microfabricated Fuel Cells To Power Integrated Circuits." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7106.
Повний текст джерелаАнотація:
Microfabricated fuel cells have been designed and constructed on silicon integrated circuit wafers using many processes common in integrated circuit fabrication, including sputtering, polymer spin coating, reactive ion etching, and photolithography. Fuel delivery microchannels were made through the use of sacrificial polymers. The characteristics of different sacrificial polymers were studied to find the most suitable for this work. A polypropylene carbonate solution containing a photo-acid generator could be directly patterned with ultraviolet exposure and thermal decomposition. The material that would serve as the fuel cells proton exchange membrane (PEM) encapsulated the microchannels. Silicon dioxide deposited by plasma enhanced chemical vapor deposition (PECVD) at relatively low temperatures exhibited material properties that made it suitable as a thin-film PEM in these devices. By adding phosphorous to the silicon dioxide recipe during deposition, a phosphosilicate glass was formed that had an increased ionic conductivity. Various polymers were tested for use as the PEM or in combination with oxide to form a composite PEM. While it did not work well alone, using Nafion on top of the glass layer to form a dual-layer PEM greatly enhanced the fuel cell performance, including yield and long-term reliability. Platinum and platinum/ruthenium catalyst layers were sputter deposited. Experiments were performed to find a range of thicknesses that resulted in porous layers allowing contact between reactants, catalyst, and the PEM. When using the deposited glasses, multiple layers of catalyst could be deposited between thin layers of the electrolyte, resulting in higher catalyst loading while maintaining porosity. The current and power output were greatly improved with these additional catalyst layers.
2
González, Guerrero MªJosé. "Enzymatic microfluidic fuel cells: from active to passive power sources." Doctoral thesis, Universitat Autònoma de Barcelona, 2015. http://hdl.handle.net/10803/322082.
Повний текст джерелаАнотація:
Esta tesis presenta el desarrollo y la fabricación de pilas de combustibles microfluídicas para aplicaciones portátiles de baja potencia. En concreto, pilas biológicas que utilizan las enzimas en la degradación de la glucosa. El trabajo está dividido en dos secciones dependiendo de si los dispositivos fabricados son activos, es decir, los reactivos son suministrados a la micropila por bombeo (Capítulo 2 y 3). O si por el contrario los reactivos fluyen sin necesidad de mecanismos externos los dispositivos serán pasivos (Capítulo 4 y 5).
En el primer capítulo de la tesis se ha llevado a cabo la primera aproximación en el desarrollo de micro pilas de combustible glucosa/O2 con el objetivo de hacer posible las primeras medidas electroquímicas con enzimas. La pila microfluídica fue construida sobre un sustrato de vidrio en el cual se grabaron electrodos de oro mediante técnicas de microfabricación. Por otro lado, se utilizó fotolitografía suave para la fabricación de los canales (con forma de Y) en PDMS. Esta forma de canal permitió fluir dos soluciones en paralelo usando una bomba de jeringa. Como primera aproximación, las enzimas se encontraban fluyendo de manera continua a través del canal. Eso provocaba experimentos caros y dificultaba su posible aplicación portátil. De este modo, el siguiente aspecto en abordarse fue la inmovilización de los biocatalizadores sobre los electrodos de la micro pila.
El Capítulo 2 presenta la fabricación de una pila de combustible que posee los biocatalizadores inmovilizados en la superficie de los electrodos lo cual hace que los biocatalizores sean aprovechados más eficientemente que en la anterior pila. Los electrodos se han fabricado utilizando resina pirolizada y se han usado por primera vez con éxito en pilas microfluídicas enzimáticas de este tipo. La pila está compuesta por diferentes capas de material plástico laminado que han sido cortadas usando un plotter de corte. Esto hace que la fabricación del dispositivo sea rápida, barata y compatible con la manufacturación a gran escala. El canal microfluídico se ha definido también sobre este tipo de material plástico, evitando el largo proceso litográfico relacionado con el PDMS. Por otro lado, el canal (en forma de Y) permite optimizar la potencia que obtenemos de la pila cuando bombeamos dos soluciones diferentes. Por otro lado, el dispositivo necesita ser simplificado para finalmente obtener una fuente de energía portátil. Con este objetivo se abordó la siguiente fase de la tesis.
El Capítulo 4 describe la fabricación de una pila microfluídica implementada utilizando sustratos de papel a través de los cuales fluyen los reactivos (de manera pasiva) por efecto capilar. Los componentes de la pila se cortaron utilizando un plotter de corte, lo que permitía fabricar dispositivos con mucha rapidez. Se probó el buen funcionamiento de una pila de combustible de papel y enzimática obteniendo valores de potencia similares a los presentados en el Capítulo 3 (donde las soluciones eran bombeadas). A partir de aquí el trabajo se centró en aproximar la pila de papel a la simplicidad de los test de flujo lateral. Así que la micro pila fue adaptada y operada con éxito usando una única solución, generando energía de una bebida comercial.
El Capítulo 5 presenta una micropila de combustible fabricada en papel mucho más sofisticada y pequeña que la del capítulo anterior. Se probó satisfactoriamente una nueva combinación de biocatalizadores que permitió trabajar utilizando muestras a pH neutro. Además, el tamaño compacto del sistema abrió la posibilidad de operar la pila de combustible con fluidos fisiológicos como por ejemplo la sangre. Finalmente, se ha demostrado que es posible tener una pila preparada para alimentar dispositivos que requieran poca demanda de energía. Sin embargo, todavía se deben hacer esfuerzos para acercar esta pila a un mundo real, debido principalmente a que el tiempo de vida de las enzimas es todavía limitado.This thesis presents the development and fabrication of microfluidic fuel cells for low power and portable applications. Specifically, biological fuel cells that use enzymes for glucose degradation. This work is divided in two sections depending on whether the fabricated devices are active, i. e. the reagents are supplied into the micro fuel cell by pumping (Chapters 2 and 3). If, on the contrary, the reagents flow without needing external mechanisms they are passive devices (Chapters 4 and 5). In the first chapter of the thesis the first approach in the development of glucose/O2 micro fuel cells was conducted in order to allow for the initial electrochemical measurements with enzymes. The microfluidic fuel cell was fabricated using a glass substrate in which gold electrodes were impressed using microfabrication techniques. On the other hand, soft lithography was used to fabricate the Y-shaped PDMS channels. This channel shape enabled to flow two solutions in parallel using a syringe pump. The enzymes were continuously flowing through the channel causing expensive experiments in addition to hindering its possible portable application. Thereby, the biocatalysts immobilization on the electrodes was next addressed in this thesis. Chapter 2 presents the fabrication of a micro fuel cell with enzymes trapped on the electrode surfaces which lead to an effective use of the biocatalysts. The electrodes were fabricated using pyrolyzed resists and were successfully used for the first time in enzymatic microfluidic fuel cells of this kind. The fuel cell was formed by different layers of plastic laminated materials cut using a cutter plotter. This promotes a fast and inexpensive device fabrication which is compatible with large scale manufacturing. The microfluidic channel was also defined on this type of plastic materials, thus avoiding the long lithographic process related to the PDMS. Moreover, this Y-shaped channel allows to optimize the power obtained from the fuel cell when two different solution are pumped into the system. Therefore, the following aspect to be addressed was the biocatalyst immobilization over the electrodes of the micro fuel cell Chapter 4 describes the construction of a microfluidic fuel cell fabricated using paper substrates. The reagents flow through this paper (in a passive way) by capillary action. The fuel cell components were cut using a cutting plotter which allows fabricating devices much faster. The proper functioning of this paper-based microfluidic fuel cell was verified obtaining similar power values to those presented in Chapter 3 (were solution were pumped). From here, the work focused on bringing the paper fuel cell closer to the simplicity of lateral flow tests. The fuel cell was then adapted and successfully operated using a single solution, generating energy from a commercial drink. Chapter 5 presents a microfluidic paper-based fuel cell smaller and more sophisticated than the one presented in previous chapter. A new combination of enzyme was tested which allowed to work with samples at neutral pH. Additionally, the compact size of the system opened the possibility to operate the paper fuel cell with physiological fluids, such as blood. Finally, it was demonstrated that was possible to have a fuel cell ready to fed devices demanding low energy. However, more efforts have to be done in the field to approach this fuel cell to a real world mainly due to the still limited lifetime of the enzymes.
3
Carlson, Amy L. "Applying fuel cells to data centers for power and cogeneration." Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/1366.
Повний текст джерела
4
Liu, Jianxing. "Contributions to Adaptative Higher Order Sliding Mode Observers : Application to Fuel Cell an Power Converters." Thesis, Belfort-Montbéliard, 2014. http://www.theses.fr/2014BELF0232/document.
Повний текст джерелаАнотація:
Les systèmes piles à combustible de type PEM pour des applications de transport reposent sur un ensemble d’auxiliaires (stockage d’hydrogène, compresseur d’air, convertisseur de puissance, humidificateur, etc) qui assurent le bon fonctionnement du système pile. La mise en place d’observateurs permet de disposer d’un outil pour reconstruire les états non mesurés de ce système; cela permet de mettre en place un contrôle par retour de sortie en vue d’optimiser les performances du système pile et ainsi d'améliorer la détection et l’isolation de défauts (FDI). Cette thèse est basée sur l’étude et la synthèse d'observateurs adaptatifs par mode glissant d’ordre supérieur, pour deux principaux auxiliaires de la pile que sont, le système d'alimentation en air et les convertisseurs de puissance associés à la pile. La première partie de la thèse est consacrée à la synthèse d’observateurs pour la reconstruction des états et à la détection et l’isolation des défauts sur le système d’alimentation en air de la PEMFC. Dans un premier temps, un observateur algébrique par mode glissant d’ordre supérieur est synthétisé pour la reconstruction de la pression partielle de l'oxygène et de l'azote. Dans un deuxième temps, un nouvel observateur adaptatif par mode glissant d’ordre deux est synthétisé pour assurer l'observation simultanée des états, l'identification des paramètres, la surveillance et la reconstruction de défaut dans le circuit d’air. Les performances des observateurs proposées ont été validées grâce à un simulateur Hardware-In-Loop (HIL) du système pile à combustible.Dans la deuxième partie, nous nous sommes intéressés à l’élaboration d’observateurs et de commande par retour de sortie pour les convertisseurs associé au système pile dans une application transport. Ainsi, une commande novatrice par mode glissant d’ordre deux, de type retour de sortie, a été élaborée pour le convertisseur AC/DC. Dans un second temps, un observateur de type modes glissants d’ordre 2 adaptatif est synthétisé pour un convertisseur de type multicellulaireAutomotive PEM Fuel Cell systems rely upon a set of auxiliary systems for proper operation, such as humidifier, air-feed compressor, power converter etc. The internal physical states of the latter are often unmeasurable, yet required for their precise control. Observers provide a means of obtaining the unmeasured states of these auxiliary systems for feedback control, optimal energy consumption and Fault Diagnosis and Isolation (FDI). This thesis is based on higher order sliding mode observer design studies for two major PEMFC auxiliary systems found in modern automobiles, the air-feed system and the power electronics system.The first part is focused on robust observation and FDI of the PEMFC air-feed systems. Sliding mode observer design and their applications to FDI have been studied in detail for this purpose and the key observation problems in this system have been identified. Based on this study, two solutions are proposed, a sliding mode algebraic observer for oxygen and nitrogen partial pressures and a novel robust adaptive-gain Second Order Sliding Mode (SOSM) observer based FDI for simultaneous state observation, parameter identification, health monitoring and fault reconstruction of the PEMFC air-feed system. The performance of the proposed observers has been validated on an instrumented Hardware-In-Loop (HIL) test bench.The observation and output feedback control problems of different power electronic converters, commonly found in fuel cell vehicles, are addressed in the next part. Robust output feedback SOSM control for three phase AC/DC converters have been presented. A robust SOSM observer for multi-cell converters has also been designed. The performance of all these designs has been demonstrated through a multi-rate simulation approach. The results highlight the robustness of the observers and controllers against parametric uncertainty, measurement noise and external disturbance
5
Staniforth, J. "The use of biogas to power a small tubular solid oxide fuel cell." Thesis, Keele University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311728.
Повний текст джерела
6
Choi, Woojin. "New approaches to improve the performance of the PEM based fuel cell power systems." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2752.
Повний текст джерелаАнотація:
Fuel cells are expected to play an important role in future power generation. However, significant technical challenges remain and the commercial breakthrough of fuel cells is hindered by the high price of fuel cell components. As is well known, the fuel cells do not provide the robust source characteristics required to effectively follow the load during significant load steps and they have limited overload-handling capability. Further, the performance of the fuel cell is significantly degraded when the CO (Carbon Monoxide) is contained in the hydrogen fuel.
In this thesis several new approaches to improve the performance of PEM based fuel cell power systems are discussed. In the first section an impedance model of the Proton Exchange Membrane Fuel Cell Stack (PEMFCS) is first proposed. This equivalent circuit model of the fuel cell stack is derived by a frequency response analysis (FRA) technique to evaluate the effects of the ripple current generated by the power-conditioning unit. Experimental results are presented to show the effects of the ripple currents.
In the second section, a fuel cell powered UPS (Uninterruptible Power Supply) system is proposed. In this approach, two PEM Fuel Cell modules along with suitable DC/DC and DC/AC power electronic converter modules are employed. A Supercapacitor module is also employed to compensate for instantaneous power fluctuations including overload and to overcome the slow dynamics of the fuel processor such as reformers. A complete design example for a 1-kVA system is presented.
In the third section, an advanced power converter topology is proposed to significantly improve the CO tolerance on PEM based fuel cell power systems. An additional two-stage dc-dc converter with a supercapacitor module is connected to the fuel cell to draw a low frequency (0.5Hz) pulsating current of the specific amplitude (20-30[A]) from the fuel cell stack. CO on the catalyst surface can be electro-oxidized by using this technique, and thereby the CO tolerance of the system can be significantly improved. Simulation and experimental results show the validity and feasibility of the proposed scheme.
7
Beccherle, Julien. "Feasibility and economics of existing PWR transition to a higher power core using annular fuel." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/44776.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Nuclear Science and Engineering, 2007.Includes bibliographical references (p. 135).
The internally and externally cooled annular fuel is a new type of fuel for PWRs that enables an increase in core power density by 50% within the same or better safety margins as the traditional solid fuel. Each annular fuel assembly of the same side dimensions as the solid fuel has 160 annular fuel rods arranged in a 13x13 array. Even at the much higher power density, the fuel exhibits substantially lower temperatures and a MDNBR margin comparable to that of the traditional solid fuel at nominal (100%) power. The major motivation for such an up-rate is reduction of electricity generation cost. Indeed, the capital cost per kWh(e) of the construction is smaller than the standard construction of a new reactor with solid fuel. Elaborating on previous work, we study the economic payoff of such an up-rate of an existing PWR given the expected cost of equipment and also cost of money using different assumptions. Especially, the fate of the already bought solid fuel is investigated. It is demonstrated that the highest return on investment is obtained by gradually loading annular fuel in the reactor core such that right before shutting the reactor down for the up-rate construction, two batches in the core are of annular fuel. This option implies running a core with a mixture of both annular fuel and solid fuel assemblies. In order to prove the technical feasibility of such an option, the thermal-hydraulics of this mixed core is investigated and the Minimum Departure From Nucleate Boiling is found to be either unaffected or even improved by using a mixed core. Consequently, a neutronic model is developped to verify and validate the neutronic feasibility of the transition from solid fuel to annular fuel.
(cont.) The overall conclusion of this work is that annular fuel is a very promising option for existing reactors to increase by 50% their power, because it enables such an uprate at very attractive return on investement. We show that, by a smart management of the transition, a return on investment of about 22 to 27 % can be achieved.
by Julien Beccherle.
S.M.
8
Jarvis, Christina M. "An evaluation of the wildlife impacts of offshore wind development relative to fossil fuel power production." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file 0.67 Mb., 123 p, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:1430770.
Повний текст джерела
9
SALOMONE, FABIO. "Addressing the challenges of the Power-to-Fuel technologies from a catalyst development and techno-economic point of view." Doctoral thesis, Politecnico di Torino, 2021. http://hdl.handle.net/11583/2907012.
Повний текст джерела
10
Gustafson, Michael K. "A Computational Approach to Simulating the Performance of a 24-Hour Solar-Fuel Cell-Hydrogen Electric Power Plant." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1369357154.
Повний текст джерела
11
Henke, Moritz [Verfasser], and Andreas [Akademischer Betreuer] Friedrich. "Pressurised solid oxide fuel cells : from electrode electrochemistry to hybrid power plant system integration / Moritz Henke. Betreuer: Andreas Friedrich." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2016. http://d-nb.info/1082538108/34.
Повний текст джерела
12
Smith, Aimée. "Multi-criteria decision making approach to optimization of fuel-mix choice for electric power generation under environmental impact constraints." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0035/MQ57739.pdf.
Повний текст джерела
13
Smith, Aimee Carleton University Dissertation Engineering Civil and Environmental. "Multi-criteria decision making approach to optimization of fuel-mix choice for electric power generation under environmental impact constraints." Ottawa, 2000.
Знайти повний текст джерела
14
Zavadil, Jan. "Sezónní akumulace využívající technologii power-to-gas." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417449.
Повний текст джерелаАнотація:
The diploma thesis is focusing on the seasonal energy storage in synthetic fuels and the Power to Gas system (P2G). The P2G enables the conversion of electrical energy in times of electricity surplus, for example by using the surplus from renewable energy sources to produce synthetic gas, particulary hydrogen and synthetic methane. The main focus is on the technical and economic assessment of P2G of the Gazela natural gas pipeline. Furthermore, it identifies the limits of production, transportation, and storage capacities of these synthetic gases. The technical analysis assumes the injection of hydrogen of a certain molar concentration, according to the four proposed scenarios, into the natural gas transmission system in the Gazela pipeline. The results have showen that an increase in the molar fraction of hydrogen in natural gas will cause problems in gas transport and will lead to an increase in the pressure losses, an increase in flow rate, and a decrease in the storage capacity of the pipeline. The economic analysis examines the use of P2G technology in Czech conditions. It demonstrates the amount of production costs for the production of 1 MWh of synthetic gas depending on the electricity price and the operating time of the production facility. The sensitivity analysis has shown that neither hydrogen nor synthetic methane is competitive next to cheap natural gas unless measures like an increased price of emission allowances or a carbon tax are taken.
15
Arsalis, Alexandros. "Thermoeconomic Modeling and Parametric Study of Hybrid Solid Oxide Fuel Cell – Gas Turbine – Steam Turbine Power Plants Ranging from 1.5 MWe to 10 MWe." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31005.
Повний текст джерелаАнотація:
Detailed thermodynamic, kinetic, geometric, and cost models are developed, implemented, and validated for the synthesis/design and operational analysis of hybrid solid oxide fuel cell (SOFC) – gas turbine (GT) – steam turbine (ST) systems ranging in size from 1.5 MWe to 10 MWe. The fuel cell model used in this thesis is based on a tubular Siemens-Westinghouse-type SOFC, which is integrated with a gas turbine and a heat recovery steam generator (HRSG) integrated in turn with a steam turbine cycle. The SOFC/GT subsystem is based on previous work done by Francesco Calise during his doctoral research (Calise, 2005). In that work, a HRSG is not used. Instead, the gas turbine exhaust is used by a number of heat exchangers to preheat the air and fuel entering the fuel cell and to provide energy for district heating. The current work considers instead the possible benefits of using the exhaust gases in an HRSG in order to produce steam which drives a steam turbine for additional power output.
Four different steam turbine cycles are considered in this M.S. thesis work: a single-pressure, a dual-pressure, a triple-pressure, and a triple-pressure with reheat. The models have been developed to function both at design (full load) and off-design (partial load) conditions. In addition, different solid oxide fuel cell sizes are examined to assure a proper selection of SOFC size based on efficiency or cost. The thermoeconomic analysis includes cost functions developed specifically for the different system and component sizes (capacities) analyzed. A parametric study is used to determine the most viable system/component syntheses/designs based on maximizing total system efficiency or minimizing total system life cycle cost.Master of Science
16
Rancruel, Diego Fernando. "Dynamic Synthesis/Design and Operation/Control Optimization Approach applied to a Solid Oxide Fuel Cell based Auxiliary Power Unit under Transient Conditions." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/26277.
Повний текст джерелаАнотація:
A typical approach to the synthesis/design optimization of energy systems is to only use steady state operation and high efficiency (or low total life cycle cost) at full load as the basis for the synthesis/design. Transient operation as reflected by changes in power demand, shut-down, and start-up are left as secondary tasks to be solved by system and control engineers once the synthesis/design is fixed. However, transient regimes may happen quite often and the system response to them is a critical factor in determining the systemâ s feasibility. Therefore, it is important to consider the system dynamics in the creative process of developing the system.
A decomposition approach for dynamic optimization developed and applied to the synthesis/design and operation/control optimization of a solid oxide fuel cell (SOFC) based auxiliary power unit (APU) is the focus of this doctoral work. Called DILGO (Dynamic Iterative Local-Global Optimization), this approach allows for the decomposed optimization of the individual units (components, sub-systems or disciplines), while taking into account the intermediate products and feedbacks which couple all of the units which make up the overall system. The approach was developed to support and enhance current engineering synthesis/design practices by making possible dynamic modular concurrent system optimization. In addition, this approach produces improvements in the initial synthesis/design state at all stages of the process and allows any level of complexity in the unitâ s modeling.
DILGO uses dynamic shadow price rates as a basis for measuring the interaction level between units. The dynamic shadow price rate is a representation of the unitâ s cost rate variation with respect to variations in the unitâ s coupling functions. The global convergence properties of DILGO are seen to be dependent on the mathematical behavior of the dynamic shadow price rate. The method converges to a â globalâ (system-level) optimum provided the dynamic shadow price rates are approximately constant or at least monotonic. This is likely to be the case in energy systems where the coupling functions, which represent intermediate products and feedbacks, tend to have a monotonic behavior with respect to the unitâ s local contribution to the systemâ s overall objective function.
Finally, DILGO is a physical decomposition used to solve system-level as well as unit-level optimization problems. The total system considered here is decomposed into three sub-systems as follows: stack sub-system (SS), fuel processing sub-system (FPS), and the work and air recovery sub-system (WRAS). Mixed discrete, continuous, and dynamic operational decision variables are considered. Detailed thermodynamic, kinetic, geometric, physical, and cost models for the dynamic system are formulated and implemented. All of the sub-systems are modeled using advanced state-of-the-art tools. DILGO is then applied to the dynamic synthesis/design and operation/control optimization of the SOFC based APU using the total life cycle cost as objective function. The entire problem has a total of 120 independent variables, some of which are integer valued and dynamic variables. The solution to the problem requires only 6 DILGO iterations.Ph. D.
17
Williams, Brian C. "The development of the eclipse process simulator and its application to the techno-economic assessment of fossil fuel based power generation technologies." Thesis, University of Ulster, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260623.
Повний текст джерела
18
Copek, Tomáš. "Ukládání elektrické energie do výhřevných plynů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-241877.
Повний текст джерелаАнотація:
This master’s thesis deals with Power to Gas technology. In this concept electrical energy is used for hydrogen production via electrolysis. Hydrogen can be injected in limited amount into natural gas grid, used for power generation via fuel cells or as a reactant for methanation process. Characteristics of hydrogen and ways of hydrogen production, storage and transport are described. Fuel cells are described as a device which uses hydrogen for power production. Crucial part of this thesis consists of a description of Power to Gas concept and a design of Power to Gas unit with electrical power of 9,5 kW. Three different units were designed for three different times of day operation. Efficiency and economical assessment was carried out for these three Power to Gas units.
19
Jung, Jin Woo. "Modeling and control of fuel cell based distributed generation systems." Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1116451881.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Ohio State University, 2005.Title from first page of PDF file. Document formatted into pages; contains xvi, 209 p.; also includes graphics. Includes bibliographical references (p. 202-209). Available online via OhioLINK's ETD Center
20
Garcia, Arregui Marcos. "Theoretical study of a power generation unit based on the hybridization of a fuel cell stack and ultracapacitors : application to the design of an aircraft emergency electrical network." Toulouse, INPT, 2007. http://ethesis.inp-toulouse.fr/archive/00000521/.
Повний текст джерелаАнотація:
Le travail présenté dans ce mémoire porte sur la conception d'un réseau électrique à base d'une pile à combustible et son organe de stockage associé. Le contexte de ce travail se place dans une application aéronautique. Les piles à combustible à air comprimé ont besoin de certains dispositifs auxiliaires qui permettent la bonne diffusion des gaz. A cause de ces dispositifs auxiliaires, la dynamique globale du système est limitée, et une hybridation avec une source de puissance auxiliaire peut être nécessaire. En outre, l'hybridation a un impact positif sur la taille du système, et peut mener à la réduction du poids et du volume du système global. Les supercapacités semblent bien adaptées pour cette mission. Étant donné que notre système est dédié à une application embarquée, le volume, le poids, le coût ainsi que la consommation d'hydrogène sont des paramètres clés pour le choix de l’une des architectures proposées. Donc, une optimisation globale du système semble nécessaireThe presented work deals with the design and conception of an electrical network from a fuel cell stack and its associated storage device. The framework of this project is an aeronautical and transport application. Air pressurized fuel cell stacks need some auxiliary devices that permits a correct gas flow through the fuel cell stack. Due to the auxiliary devices, the fuel cell dynamics performances may be limited, and a power buffer is required to support power peaks. Furthermore, hybridization has a positive effect in the system size, and can lead to reduce the global system weight and volume. Ultracapacitos seem to be well adequate for this purpose. Due to the transport application, the system hydrogen consumption, volume, weight and cost are essential parameters. Due to the transport application, the system hydrogen consumption, volume, weight and cost are sizing essential parameters. Therefore a global system optimization seems mandatory in this cas
21
Garcia, Arregui Marcos Astier Stéphan Turpin Christophe. "Theoretical study of a power generation unit based on the hybridization of a fuel cell stack and ultracapacitors application to the design of an aircraft emergency electrical network /." Toulouse : INP Toulouse, 2008. http://ethesis.inp-toulouse.fr/archive/00000521.
Повний текст джерела
22
Tshamala, Mubenga Carl. "Simulation and control implications of a high-temperature modular reactor (HTMR) cogeneration plant." Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86264.
Повний текст джерелаАнотація:
Thesis (MScEng)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Traditionally nuclear reactor power plants have been optimised for electrical power generation only. In the light of the ever-rising cost of dwindling fossil fuel resources as well the global polluting effects and consequences of their usage, the use of nuclear energy for process heating is becoming increasingly attractive. In this study the use of a so-called cogeneration plant in which a nuclear reactor energy source is optimised for the simultaneous production of superheated steam for electrical power generation and process heat is considered and analysed. The process heat superheated steam is generated in a once-through steam generator of heat pipe heat exchanger with intermediate fluid while steam for power generation is generated separately in a once-through helical coil steam generator. A 750 °C, 7 MPa helium cooled HTMR has been conceptually designed to simultaneously provide steam at 540 °C, 13.5 MPa for the power unit and steam at 430 °C, 4 MPa for a coal-to-liquid fuel process. The simulation and dynamic control of such a typical cogeneration plant is considered. In particular, a theoretical model of a typical plant will be simulated with the aim of predicting the transient and dynamic behaviour of the HTMR in order to provide guideline for the control of the plant under various operating conditions. It was found that the simulation model captured the behaviour of the plant reasonably well and it is recommended that it could be used in the detailed design of plant control strategies. It was also found that using a 1500 MW-thermal HTMR the South African contribution to global pollution can be reduced by 1.58%.
AFRIKAANSE OPSOMMING: Tradisioneel is kernkragaanlegte vir slegs elektriese kragopwekking geoptimeer. In die lig van die immer stygende koste van uitputbare fossielbrandstohulpbronne asook die besoedelingsimpak daarvan wêreldwyd, word die gebruik van kernkrag vir prosesverhitting al hoe meer aanlokliker. In hierdie studie word die gebruik van ‘n sogenaamde mede-opwekkingsaanleg waarin ‘n kernkragreaktor-energiebron vir die gelyktydige produksie van oorverhitte stoom vir elektriese kragopwekking en proseshitte oorweeg ontleed word. Die oorvehitte stoom word in ‘n enkeldeurvloei-stoomopwekking van die hittepyp-hitteruiler met tussenvloeistof opgewek en stoom vir kragopwekking word apart in ‘n enkeldeurvloei-spiraalspoel-stoomopwekker opgewek. ‘n 750 °C, 7 MPa heliumverkoelde HTMR is konseptueel ontwerp vir die gelytydige veskaffing van stoom by 540 °C, 13.5 MPa, vir die kragopwekkings eenheid, en stoom by 430 °C, 4 MPa, vir ‘n steenkool-tot-vloeibare (CTL) brandstoff proses. Die simulasie en dinamiese beheer van ‘n tipiese HTMR mede-opwekkingsaanleg word beskou. ‘n die besonder word ‘n teoretiese model van die transiënte en dinamiese gedrag van die aanleg gesimuleer om sodoene riglyne te identifiseer vir die ontwikkeling van dinamiese beheer strategië vir verskillende werkstoestande van die aanleg. Daar was ook gevind dat die simulasie model van die aanleg se gedrag goed nageboots word en dat dit dus gebruik kan word vir beheer strategie doeleindes. Indien so ‘n 1500 MW-termies HTMR gebruik word sal dit die Suid Afrikaanse besoedling met 1.58% sal kan verminder.
23
Joo, Choonshik, and Martin Stangl. "Application of Power Regenerative Boom system to excavator." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2016. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-200461.
Повний текст джерелаАнотація:
This paper is presenting the application of Power Regenerative Boom(PRB) system to excavator. In order to increase the fuel efficiency of the excavator, potential energy of the front structure is recuperated by the hydraulic hybrid system with electric-hydraulic control, during boom down motion. Charged energy into accumulator is reused after boom down motion, the pressurized oil goes to hydraulic motor. The hydraulic motor is mounted on the engine PTO(Power Take-Off), therefore output torque of the hydraulic motor assists the diesel engine directy, it leads to decrease fuel consumption of diesel engine. After the system design and simulation investigation, the presented system was installed into Doosan’s 38ton excavator, DX380LC-3 model, and the energy saving result was verified by a digging and dumping repetition test. The test result shows that fuel consumption was dramatically decreased by 5.0 L/hr compared to the standard DX380LC-3.
24
Fillis, Vernon W. "First Order Assessment of Heat Transfer due to the Loss of Inventory in a Spent Fuel Pool." Master's thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29599.
Повний текст джерелаАнотація:
The Fukushima Daiichi Nuclear Power Plant accident created renewed international interest in the behaviour of spent fuel subsequent to a complete loss of water inventory in a spent fuel pool (SFP). The study conducted in this dissertation serves as a starting point in gaining an understanding of the thermal hydraulics and associated heat transfer processes involved when spent fuel assemblies (SFAs) become uncovered in air. The complete loss of cooling in a SFP is a complex 3-D problem, hence several simplifications were necessary in this research to narrow the scope. Further, due to the complexity of this topic, the results obtained serves purely as a first order approximation. Accordingly, the Flownex systems CFD code (version 8.6.1.2630) was used to simulate the thermal response of the uncovered SFAs in the SFP of a typical Pressurised Water Reactor (PWR) during a severe accident scenario. Two network models were developed. The first was to identify the dominant heat transfer mechanisms with-in the spent fuel pool and it therefore accounted for a range of physics. This included convective heat transfer through the composite SFA channel walls, conduction along the vertical axial direction of the SFAs and through the inner and outer rack wall as well as through the fuel building (FB) roof and side walls. The model also took into account the radiative heat transfer from the cladding surface of the composite SFAs to the FB roof and side walls. This network model informed that the heat transfer with-in the SFA during the considered extreme accident scenario is dominated by radiative heat transfer. This informed the development of an improved 2-D network model using conduction elements which were specially calibrated in this work to account for radiative heat loss. An effective conduction for the fuel volume which is dependent on temperature was determined and was used to assess the severe accident. Transient results showed that the spent fuel may reach cladding oxidation temperature within circa 10.5 hrs after a complete loss of inventory.
25
Mitchell, Catherine. "The renewable non-fossil fuel obligation : a case study of the barriers to energy technology development." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240632.
Повний текст джерела
26
Del, Barga Christopher. "Design and Optimization of a Mobile Hybrid Electric System to Reduce Fuel Consumption." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/76797.
Повний текст джерелаАнотація:
The high costs and high risks of transporting fuel to combat zones make fuel conservation a dire need for the US military. A towable hybrid electric system can help relieve these issues by replacing less fuel efficient standalone diesel generators to deliver power to company encampments. Currently, standalone generators are sized to meet peak demand, even though peak demand only occurs during short intervals each day. The average daily demand is much less, meaning generators will be running inefficiently most of the day.
In this thesis, a simulation is created to help determine an optimal system design given a load profile, size and weight constraints, and relocation schedule. This simulation is validated using test data from an existing system. After validation, many hybrid energy components are considered for use in the simulation. The combination of components that yields the lowest fuel consumption is used for the optimal design of the system. After determining the optimal design, a few design parameters are varied to analyze their effect on fuel consumption.
The model presented in this thesis agrees with the test data to 7% of the measured fuel consumption. Sixteen system configurations are run through the simulation and their results are compared. The most fuel efficient system is the system that uses a 3.8kW diesel engine generator with a 307.2V, maximum capacity LiFeMgPO? battery pack. This system is estimated to consume 21% less fuel than a stand-alone generator, and up to 28% less when solar power is available.Master of Science
27
Zhang, Yusheng. "Development of a bench scale single batch biomass to liquid fuel facility." Thesis, University of Fort Hare, 2014. http://hdl.handle.net/10353/811.
Повний текст джерелаАнотація:
The research described in this dissertation was motivated by the global demand for energy that is not dependent on coal, oil, natural gas and other non-renewable fossil fuels. The technology used in this project is related to the use of biomass to produce a viable alternative to conventional sources of fuel. A bench scale biomass to liquid (BTL) facility was built and tested. This produced results confirming the feasibility of the BTL process. The findings of the pilot study outlined in this dissertation justified the conclusion that the next step will be to expand the capacity and productivity of the BTL pilot plant to an industrial scale. Biomass comes from a variety of renewable sources that are readily available. In this case, the material used in the fixed bed biomass gasification facility to generate wood gas was agricultural and forestry waste, such as straw and wood chips. The gasifier had the capacity to produce up to 10 cubic metres/hr of gas with a carbon monoxide and hydrogen content of between 20–40% by volume, when it was operated at ambient pressure and with air as the oxidizer. The gas, produced at a temperature above 700º C, was cooled in a quench/water scrubber in order to remove most of the mechanical impurities (tars and water-soluble inorganic particles), condensed and dried with corn cobs before being compressed in cylinders at over 100 bar (g) for use in the Fischer-Tropsch Synthesis (FTS). The syngas was subjected further to a series of refining processes which included removal of sulphur and oxygen. The sulphur removal technology chosen entailed applying modified activated carbon to adsorb H2S with the help of hydrolysis in order to convert organic sulphur impurities into H2S which reduced the sulphur content of the gas to less than 5 ppbv. Supported cobalt catalyst (100 grams), were loaded into a single-tube fixed bed FT reactor with an inner diameter of 50 mm. The reactor was fitted with a heating jacket through which, heated oil ran to cool the reactor during a normal reaction occurring at < 250 ºC, while nitrogen was used in the heating jacket during reduction, which occurred at temperatures up ~ 350 ºC. The FTS reaction was carried out at different pressures and temperatures. Liquid and wax products were produced from the facility. The properties of the liquid and solid hydrocarbons produced were found to be the same as FT products from other feed stocks, such as natural gas and coal.
28
Sternberg, Kyle Matthew. "High power, high efficiency, low cost DC/DC converters for laser test equipment and residential fuel cell applications." Thesis, Montana State University, 2009. http://etd.lib.montana.edu/etd/2009/sternberg/SternbergK1209.pdf.
Повний текст джерелаАнотація:
In this work two low cost, high efficiency, high power DC/DC converters are developed. The first converter is targeted for industrial laser applications. The converter is designed for a 400 volt input voltage and a 0-36V output voltage and 0-40A output with a maximum power output of 1500 watts at a cost less than $0.30 / watt. To achieve a high efficiency and low cost at this power level a zero-voltage switched full bridge converter is used. This technology increases the efficiency of the converter past 90% while reducing the size of the components. The converter was built and tested and achieved a 91.5% efficiency at full load. The total cost was $0.28 / watt. This converter met all the design goals while exceeding the cost goals. The second converter is targeted for residential fuel cell applications. This converter utilizes the technology developed for the industrial converter. This residential converter is designed for an input of 26-42 volts at 190 amps and an output of 400 volts and 12 amps at a power level of 5000 watts while maintaining a $40/kilowatt cost goal. To achieve the low cost and high efficiency design goals the converter uses several technologies in its construction. Like the converter for industrial applications this converter utilizes zero voltage switching full bridge converter. To compensate for the high input current a unique multiphase design was designed for the application. A unique parallel input / series output topology and three interleaved converters split the input current to increase the efficiency of the converter. This unique topology increases the switching frequency on the secondary side which reduces the side of the passive components, reducing cost. The converter was built and tested at a light load to verify its operation versus the theory. An estimated 96% efficiency at full load is possible using this topology. The total cost was $39 / kilowatt.
29
Benedetto, Michael V. "A possible solution for the U.S. Navy's addiction to petroleum : a business case analysis for transitioning the U. S. Navy from petroleum to synthetic fuel resources /." Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion.exe/07Mar%5FBenedetto.pdf.
Повний текст джерелаАнотація:
Thesis (M.S. in Operations Research)--Naval Postgraduate School, March 2007.Thesis Advisor(s): Daniel A. Nussbaum. "March 2007." Includes bibliographical references (p. 95-99). Also available in print.
30
Wang, Ying-Chin. "Using Red Blood Cells in Microbial Fuel Cell Catholyte Solution to Improve Electricity Generation." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1398945679.
Повний текст джерела
31
Bahrami, Milad. "Contribution to the development of a fuel cell management system." Electronic Thesis or Diss., Université de Lorraine, 2020. http://www.theses.fr/2020LORR0025.
Повний текст джерелаАнотація:
L'intermittence des ressources constitue le principal défi de l'utilisation de la production d'électricité à partir d'énergies renouvelables. Par conséquent, de nouveaux moyens de stockage de l'électricité sont inévitables. L'hydrogène, en tant que vecteur énergétique, peut résoudre ce problème. L'hydrogène peut être produit en utilisant l'énergie excédentaire des sources d'énergie renouvelables. C'est pourquoi une pile à combustible à membrane électrolytique polymère (PEMFC), en tant que dispositif capable de convertir directement l'énergie de l'hydrogène en électricité, est un élément important de cette solution. Le coût et la durabilité sont les principaux défis à relever pour permettre la diffusion de cette technologie sur le marché de masse. Dans le cadre d'un micro-réseau multi-vecteurs, un système de gestion des piles à combustible (FCMS) est proposé et conçu dans cette thèse. Il permet d'optimiser la fiabilité et la durée de vie des PEMFC en contrôlant l'état de fonctionnement des cellules pour éviter les instabilités électrochimiques. Une méthode de diagnostic ainsi qu'une nouvelle architecture d'électronique de puissance hybride sont le cœur de ce FCMS. La méthode de diagnostic peut détecter la plupart des instabilités du FCMS grâce à un nouveau modèle en temps réel. Ce modèle peut simuler une cellule dans son environnement de pile. Une architecture d'électronique de puissance hybride est développée pour ce FCMS qui garantit un meilleur vieillissement du système en contrôlant séparément la puissance fournie par les cellules. L'architecture d'électronique de puissance proposée est hybridée par un supercondensateur (SC) qui peut compenser la faible dynamique des PEMFC en fournissant les profils de charge dynamiques rapides. Une méthode de contrôle en logique floue (FLC) est développée dans le cadre du FCMS pour modifier la puissance de référence des groupes de cellules sur la base des données du modèle. Le système proposé et ses différentes parties sont validés par les résultats de la simulation et de l'expérimentationThe essential challenge in using renewable energy-based electricity generation is the intermittency of resources. Therefore, new ways to store electricity is inevitable. Hydrogen as an energy carrier can deal with this issue. Hydrogen can be produced by using the excess energy of renewable energy sources. Therefore, a Polymer Electrolyte Membrane Fuel Cell (PEMFC) as a device that can directly convert hydrogen energy to electricity is an important part of this solution. The cost and durability are the major challenges to enable the diffusion of this technology in the mass market. In the frame of a multi-vectors microgrid, a Fuel Cell Management System (FCMS) is proposed and designed in this thesis that allows optimizing the reliability and life of PEMFCs through controlling the operating condition of cells to avoid electrochemical instabilities. A proposed diagnostic method along with a new hybrid power electronics architecture is the core of this FCMS. The diagnostic method can detect most of the FCMS instabilities by a new comprehensive real-time model. This model can simulate a cell in its stack environment. A hybrid power electronics architecture is developed for this FCMS that guarantees better aging of the system by separately manipulating the supplied power of cells. The proposed power electronics architecture is hybridized by a Supercapacitor (SC) that can compensate for the low dynamic of PEMFCs in supplying the fast dynamic load profiles. A Fuzzy Logic Control (FLC) method is developed as a part of the FCMS to change the reference power of the cell groups based on the model data. The proposed system and its different parts are validated through the simulation and experimental results
32
Chen, Yingwen, Liuliu Chen, Peiwen Li, Yuan Xu, Mengjie Fan, Shemin Zhu, and Shubao Shen. "Enhanced performance of microbial fuel cells by using MnO2/Halloysite nanotubes to modify carbon cloth anodes." PERGAMON-ELSEVIER SCIENCE LTD, 2016. http://hdl.handle.net/10150/621214.
Повний текст джерелаАнотація:
The modification of anode materials is important to enhance the power generation of MFCs (microbial fuel cells). A novel and cost-effective modified anode that is fabricated by dispersing manganese dioxide (MnO2) and HNTs (Halloysite nanotubes) on carbon cloth to improve the MFCs' power production was reported. The results show that the MnO2/HNT anodes acquire more bacteria and provide greater kinetic activity and power density compared to the unmodified anode. Among all modified anodes, 75 wt% MnO2/HNT exhibits the highest electrochemical performance. The maximum power density is 767.3 mWm(-2), which 21.6 higher than the unmodified anode (631 mW/m(2)). Besides, CE (Coulombic efficiency) was improved 20.7, indicating that more chemical energy transformed to electricity. XRD (X-Ray powder diffraction) and FTIR (Fourier transform infrared spectroscopy) are used to characterize the structure and functional groups of the anode. CV (cyclic voltammetry) scans and SEM (scanning electron microscope) images demonstrate that the measured power density is associated with the attachment of bacteria, the microorganism morphology differed between the modified and the original anode. These findings demonstrate that MnO2/FINT nanocomposites can alter the characteristics of carbon cloth anodes to effectively modify the anode for practical MFC applications. (C) 2016 Elsevier Ltd. All rights reserved.
33
Ramirez, Rivera Victor Manuel. "Energy management of lossy multi-port to fuel cell-based systems." Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112087/document.
Повний текст джерелаАнотація:
Dans de nombreux réseaux, la régulation efficace du transfert d'énergie entre les sous-systèmes de production, de stockage et d'utilisation demeure un sujet difficile à traiter. Dans cette thèse on a proposent une nouvelle stratégie pour atteindre cet objectif, ainsi que sa mise en œuvre. Le dispositif est appelé routeur d'énergie dynamique (RED), parce que, contrairement à la pratique actuelle, l'asservissement de l'écoulement de puissance se fait sans s'appuyer sur des hypothèses stationnaire. Une hypothèse clé pour le bon fonctionnement du RED est que la dissipation du système est négligeable. Toutefois, en présence de pertes en ligne le RED initial n'est plus opérationnel, car il est base sur l'hypothèse clé de non dissipation des interconnections. Dans ce travail, un nouveau RED prenant en compte la présence de pertes est proposé. Des preuves de l'amélioration des performances sont présentées en simulation comme en expérimentation. Un complément de ce travail a été réalisée sur l'estimation des paramètres d'une pile à combustible du type Polymer Exchange Membrane (PEM) dans le but de concevoir un estimateur convergeant sur un grand domaine (convergence globale). Ce dernier utilise des principes d'immersion et d'invariance développés récemment dans la théorie des asservissementsEfficient regulation of the energy transfer between generating, storage and load subsystems is a topic of current practical interest. A new strategy to achieve this objective, together with its corresponding power electronics implementation, was recently proposed in this thesis work. The device is called dynamic energy router (DER) because, in contrast with current practice, the regulation of the direction and rate of change of the power flow is done without relying on steady–state considerations. A key assumption for the correct operation of the DER is that dissipation in the system is negligible. Unfortunately, in the presence of dissipation the original DER ceases to be operational. In this thesis a new DER that takes into account the presence of losses is proposed. Simulation and experimental evidence of the performance improvement with the new DER are presented. As a complement of this work a global convergent estimator of parameters of Polymer Exchange Membrane Fuel Cell (PEMFC) was designing by using the principles or “Immersion and Invariance” recently reported in control theory
34
Walker, Devin Mason. "Catalytic Tri-reforming of Biomass-Derived Syngas to Produce Desired H2:CO Ratios for Fuel Applications." Scholar Commons, 2012. http://scholarcommons.usf.edu/etd/4250.
Повний текст джерелаАнотація:
This study focuses on upgrading biomass derived syngas for the synthesis of liquid fuels using Fischer-Tropsch synthesis (FTS). The process includes novel gasification of biomass via a tri-reforming process which involves a synergetic combination of CO2 reforming, steam reforming, and partial oxidation of methane. Typical biomass-derived syngas H2:CO is 1:1 and contains tars that deactivate FT catalyst. This innovation allows for cost-effective one-step production of syngas in the required H2:CO of 2:1 with reduction of tars for use in the FTS. To maximize the performance of the tri-reforming catalyst, an attempt to control oxygen mobility, thermal stability, dispersion of metal, resistance to coke formation, and strength of metal interaction with support is investigated by varying catalyst synthesis parameters. These synthesis variables include Ce and Zr mixed oxide support ratios, amount Mg and Ni loading, and the preparation of the catalyst. Reaction conditions were also varied to determine the influences reaction temperature, gas composition, and GHSV have on the catalyst performance. Testing under controlled reaction conditions and the use of several catalyst characterization techniques (BET, XRD, TPR, XAFS, SEM-EDS, XPS) were employed to better explain the effects of the synthesis parameters. Applications of the resulting data were used to design proof of concept solar powered BTL plant. This paper highlights the performance of the tri-reforming catalyst under various reaction conditions and explains results using catalyst characterization.
35
Gibrael, Nemir, and Hamse Hassan. "HYDROGEN-FIRED GAS TURBINE FOR POWER GENERATION WITH EXHAUST GAS RECIRCULATION : Emission and economic evaluation of pure hydrogen compare to natural gas." Thesis, Mälardalens högskola, Framtidens energi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-42306.
Повний текст джерелаАнотація:
The member states of European Union aim to promote the reduction of harmful emissions. Emissions from combustion processes cause effects on human health and pose environmental issues, for example by increasing greenhouse effect. There are two ways to reduce emissions; one is to promote renewable energy sources and the other to utilize more effectively the available fossil fuels until a long-term solution is available. Hence, it is necessary to strive for CO2 mitigation technologies applied to fossil fuels. Low natural gas prices together with high energy efficiency have made gas turbines popular in the energy market. But, gas turbine fired with natural gas come along with emissions of CO2, NOx and CO. However, these disadvantages can be eliminated by using gas turbine with precombustion CO2 capture, separating carbon from the fuel by using fuel reforming process and feeding pure hydrogen as a fuel. Hydrogen fired gas turbines are used in two applications such as a gas turbine with pre-combustion CO2 capture and for renewable power plants where hydrogen is stored in case as a backup plan. Although the CO2 emissions are reduced in a hydrogen fired gas turbine with a pre-combustion CO2 capture, there are still several challenges such as high flame temperatures resulting in production of thermal NOx. This project suggests a method for application of hydrogen fired gas turbine, using exhaust gas recirculation to reduce flame temperature and thus reducing thermal NOx. A NOx emission model for a hydrogen-fired gas turbine was built from literature data and used to select the best operating conditions for the plant. In addition, the economic benefits of switching from natural gas to pure hydrogen are reported. For the techno-economic analysis, investment costs and operating costs were taken from the literature, and an economic model was developed. To provide sensitivity analysis for the techno-economic calculation, three cases were studied. Literature review was carried out on several journal articles and websites to gain understanding on hydrogen and natural gas fired gas turbines. Results showed that, in the current state, pure hydrogen has high delivery cost both in the US and Europe. While it’s easy to access natural gas at low cost, therefore in the current state gas turbine fired with natural gas are more profitable than hydrogen fired gas turbine. But, if targeted hydrogen prices are reached while fuel reforming process technology are developed in the coming future the hydrogen fired gas turbine will compete seriously with natural gas.
36
BARUA, SUKHENDU LAL. "APPLICATION OF CONDITIONAL SIMULATION MODEL TO RUN-OF-MINE COAL SAMPLING FREQUENCY DETERMINATION AND COAL QUALITY CONTROL AT THE POWER PLANT (BLENDING, GOAL PROGRAMMING, MICROCOMPUTER)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187940.
Повний текст джерелаАнотація:
Run-of-mine (ROM) coal sampling is one of the most important factors in determining the disposition of ROM coal for an overall emission control strategy. Determination of the amount of sample, or still better, the frequency of ROM coal sampling is thus essential to the analysis of overall emission control strategies. A simulation model of a portion of the Upper Freeport coal seam in western Pennsylvania was developed employing conditional simulation. On the simulated deposit, different mining methods were simulated to generate ROM coal data. ROM coal data was statistically analyzed to determine the sampling frequency. Two schemes were suggested: (1) the use of geostatistical techniques if there is spatial correlation in ROM coal quality, and (2) the use of classical statistics if the spatial correlation in ROM coal quality is not present. Conditions under which spatial correlation in ROM coal quality can be expected are also examined. To link the ROM coal and coals from other sources to coal stockpiles and subsequently to solve coal blending problems, where varying qualities of stockpiled coals are normally used, an interactive computer program was developed. Simple file-handling, for stockpiling problems, and multi-objective goal programming technique, for blending problems, provided their solutions. The computer program was made suitable for use on both minicomputer and microcomputer. Menu-driven and interactive capabilities give this program a high level of flexibility that is needed to analyze and solve stockpiling and blending problems at the power plant.
37
Anosike, Nnamdi Benedict. "Technoeconomic evaluation of flared natural gas reduction and energy recovery using gas-to-wire scheme." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/8625.
Повний текст джерелаАнотація:
Most mature oil reservoirs or fields tend to perform below expectations, owing to
high level of associated gas production. This creates a sub-optimal performance
of the oil production surface facilities; increasing oil production specific
operating cost. In many scenarios oil companies flare/vent this gas. In addition
to oil production constraints, associated gas flaring and venting consists an
environmental disasters and economic waste. Significant steps are now being
devised to utilise associated gas using different exploitation techniques. Most of
the technologies requires large associated gas throughput.
However, small-scale associated gas resources and non-associated natural gas
reserves (commonly referred to as stranded gas or marginal field) remains
largely unexploited. Thus, the objective of this thesis is to evaluate techno-
economic of gas turbine engines for onsite electric power generation called gas-
to-wire (GTW) using the small-scaled associated gas resources. The range of
stranded flared associated gas and non-associated gas reserves considered is
around 10 billion to 1 trillion standard cubic feet undergoing production decline.
The gas turbine engines considered for power plant in this study are based on
simple cycle or combustion turbines. Simple cycle choice of power-plant is
conceived to meet certain flexibility in power plant capacity factor and
availability during production decline. In addition, it represents the basic power
plant module cable of being developed into other power plant types in future to
meet different local energy requirements.
This study developed a novel gas-to-wire techno-economic and risk analysis
framework, with capability for probabilistic uncertainty analysis using Monte
Carlo simulation (MCS) method. It comprises an iterative calculation of the
probabilistic recoverable reserves with decline module and power plant
thermodynamic performance module enabled by Turbomatch (an in-house
code) and Gas Turb® software coupled with economic risk modules with
@Risk® commercial software. This algorithm is a useful tool for simulating the
interaction between disrupted gas production profiles induced by production
decline and its effect on power plant techno-economic performance over
associated gas utilization economic life. Furthermore, a divestment and make-
up fuel protocol is proposed for management of gas turbine engine units to
mitigate economical underperformance of power plant regime experienced due
to production decline.
The results show that utilization of associated gas for onsite power generation is
a promising technology for converting waste to energy. Though, associated gas
composition can be significant to gas turbine performance but a typical Nigerian
associated gas considered is as good as a regular natural gas. The majority of
capital investment risk is associated with production decline both natural and
manmade. Finally, the rate of capital investment returns decreases with smaller
reserves.
38
Kong, Suyao. "Advanced passivity-based control for hybrid power systems : application to hybrid electric vehicles and microgrids." Thesis, Bourgogne Franche-Comté, 2020. http://indexation.univ-fcomte.fr/nuxeo/site/esupversions/a01b06c5-fb6c-452d-bd16-02b269cd0bb9.
Повний текст джерелаАнотація:
Un système hybride à base de pile à combustible (PàC) est une solution efficace pour faire face aux problèmes de pollution atmosphérique et de pénurie des combustibles fossiles. Cette thèse se concentre sur la conception de la commande pour les systèmes d'alimentation hybrides à base de PàC, et appliquée à deux applications : le véhicule électrique et le centre de données alimenté par un micro-réseau.Tout d'abord, cette thèse propose une commande basée sur la passivité pour un système hybride PàC/supercondensateurs (SCs). Cette commande a été conçue via la méthode de conception IDA-PBC (Interconnection and Damping Assignment - Passivity Based Control), afin de résoudre le problème de coordination des convertisseurs. L'état de charge des SCs ainsi que toutes les limitations sont intégrés directement dans la loi de commande. Un banc d'essais PHIL (Power Hardware-in-the-loop) est utilisé pour la validation. Ensuite, un filtre de Kalman étendu (EKF) est combiné avec la commande proposée, pour prévoir l'état de santé (SoH) de la pile à combustible. Enfin, un banc d'essais HIL (Hardware-in-the-loop) basé sur un FPGA INTEL / ALTERA est conçu afin de valider le fonctionnement des algorithmes en temps réel pour un véhicule commercial.Pour l'application à un micro-réseau, une commande passive est proposée pour un système hybride comprenant des panneaux photovoltaïques, une PàC, des SCs et un électrolyseur. La faisabilité de cette commande est validée par les résultats expérimentaux sur un banc d'essai PHIL. Ce travail est intégré au projet ANR DATAZERO.La nouveauté principale de cette commande est qu'elle intègre certaines contraintes de composants directement dans la loi de commande, en préservant la stabilité de l’ensemble du système, en boucle ferméeA Fuel cell (FC) hybrid power system is a promising solution to deal with the atmospheric pollution and fossil fuels shortage problems. This thesis focuses on the controller design for FC hybrid power systems, towards two applications: the hybrid electrical vehicle and the microgrid-powered datacenter.Firstly, this thesis proposes an advanced passivity-based control for a FC/super-capacitors (SCs) hybrid system. In order to solve the converters coordination problem, a controller designed using the design method Interconnection and Damping Assignment - Passivity-Based Control (IDA-PBC) is applied, which considers the state-of-charge of the SCs as well as voltage and current limitations. The proposed controller is validated on a Power Hardware-in-the-loop (PHIL) platform. Then an Extended Kalman Filter (EKF) is applied to forecast the State-of-Health (SoH) of the fuel cell and is combined with the proposed controller. Finally, a Hardware-in-the-loop (HIL) platform based on an INTEL/ALTERA FPGA is designed in order to validate the real-time operation of the algorithms for a specific case study with a commercial vehicle.For microgrid applications, a passivity-based controller for a hybrid power supply system for a green datacenter is proposed, including photovoltaic panels, a fuel cell, SCs and an electrolyzer. The feasibility of this non-linear controller is proven by the simulation results and experimental validation on a PHIL test bench. This work is integrated into the ANR DATAZERO project.The main novelty of the proposed controller is that it integrates some component constraints directly into the controller equations, while the locally asymptotic stability of the whole closed-loop system is preserved
39
Pietrelli, Andrea. "Electrical valorization of MFC : application to monitoring." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEC001/document.
Повний текст джерелаАнотація:
Dans les dernières années, l'utilisation intensive des combustibles fossiles a déclenché une crise mondiale due à la forte production de polluants et à la réduction des stocks, en raison de sa nature de source d'énergie non renouvelable. Parce que l'utilisation généralisée des combustibles fossiles a entraîné la production de grandes quantités de CO2, ce qui est un facteur aggravant du réchauffement de la planète. Les piles à combustible microbiennes (MFC) représentent une technique de récupération d'énergie qui convertit l'énergie chimique des composés organiques en énergie électrique par le biais de réactions catalytiques de micro-organismes. La MFC peut être considérée comme un archétypique de système microbien bioélectrochimique (BES), qui exploite l’activité bio-électrocatalytique de micro-organismes vivants pour la génération de courant électrique. Durant la dernière décennie, l’évolution de l’électronique de faible consommation a rendu la technologie des MFC plus attrayante, car elle commence à pouvoir fournir une énergie comparable à celle consommée par des périphériques dit à faible consommation, comme un nœud de réseau de capteurs sans fil (WSN). En plus, les MFC ont gagné en intérêt car elles peuvent générer de l'énergie électrique tout en traitant des déchets. Contrairement aux autres piles à combustible, les MFC peuvent générer en permanence une énergie propre à une température ambiante, à la pression atmosphérique et à un pH neutre, sans entretien supplémentaire. Les seuls sous-produits sont le CO2 et H2O, qui ne nécessitent aucune manipulation supplémentaire, car le CO2 produit est biogénique, ce qui est inclus dans le cycle du carbone biogéochimique, évitant l'émission nette de carbone dans l'atmosphère. Ce manuscrit examine certains aspects liés à la technologie des piles à combustible microbiennes, depuis les réactions chimiques jusqu’aux systèmes de gestion de l'énergie requis pour exploiter la puissance fournie par les MFC. Une campagne expérimentale a été menée sur les MFCs concernant la caractérisation électrique, la connexion multiple des MFCs et l’influence des principaux paramètres qui affectent les performances de conversion de l’énergie. Le contexte de la pile à biocarburant est introduit et les principes de base de fonctionnement et les applications principales sont expliqués. L'enquête comprend une évaluation de l'impact des différents matériaux d'électrode, du substrat utilisé et des bactéries impliquées dans le processus chimique. Une perspective consiste à ajuster les paramètres afin de maximiser la production d'électricité. La conception spécifique de nos MFC de laboratoire est également présentée. Les essais expérimentaux ont été effectués sur deux types de réacteurs : la pile à combustible microbienne terrestre et la pile à combustible microbienne à eau usée. Un système de mesure approprié est présenté, il est spécialement conçu pour les tests sur les MFC. Il est capable d'assurer une mesure précise de toutes les valeurs et paramètres électriques nécessaires à la caractérisation électrique des réacteurs dans une configuration unique ou dans une connexion multiple. Les solutions utilisées pour alimenter les WWMFC étaient différentes et dans certains cas, on utilisait de vraies eaux usées, alors que dans d'autres, des solutions synthétisées appropriées étaient conçues à cet effet. Les méthodes de synthèse des solutions sont décrites. L'influence des principaux paramètres tels que le pH et la température a été analysée pour les deux types de cellules. La campagne expérimentale comprend des mesures de réacteurs en configuration unique ou disposées dans des connexions en série ou en parallèle. Les résultats confirment l'augmentation de la tension dans le cas de connexions en série et l'augmentation de la puissance dans le cas de connexions en parallèle. [...]In recent years, the extensive use of fossil fuels has triggered into a global crisis due to high pollution and stock reduction, because of its nature of non-renewable source of energy. Because the wide use of fossil fuels has led to the production of high amounts of CO2, as a result is a trigger of the global warming issue. Microbial fuel cells (MFCs) is an energy harvesting technique that converts chemical energy from organic compounds to electrical energy through catalytic actions of microorganisms. MFC can be considered as archetypical microbial Bioelectrochemical Systems (BESs), that exploit the bio-electrocatalytic activity of living microorganisms for the generation of electric current. In the past decade, the evolution of low power electronics has made MFCs technology more attractive, because it has begun to be able to power low-power devices forming complete systems, such as the nodes of a wireless sensor network (WSN). Moreover, MFCs gained more interest because they can generate electric power while treating wastes. Unlike other fuel cells, MFCs can continuously generate clean energy at normal temperature, atmospheric pressure, and neutral pH value without any supplementary maintenance. The only by-products are CO2 and H2O, which do not require additional handling. The production of CO2 is part of a short duration carbon cycle. The CO2 produced is biogenic, which is included in the biogeochemical carbon cycle, avoiding net carbon emission into atmosphere. This manuscript examines many aspects related to microbial fuel cell technology from chemical reactions inside the cells to the energy management systems required to exploit energy delivered from MFCs for practical usage in autonomous sensors. Experimental campaign was performed on MFCs regarding electrical characterization, multiple connections of MFCs and influence of main parameters that affect energy conversion performances. The experimental tests were performed on two different lab-scale reactor typologies: terrestrial microbial fuel cell and waste water microbial fuel cell. A survey is presented about different proposed energy management systems and other devices able to build a node of a WSN powered by MFCs
40
Franco, Alejandro A. "A multiscale modeling framework for the transient analysis of PEM Fuel Cells - From the fundamentals to the engineering practice." Habilitation à diriger des recherches, Université Claude Bernard - Lyon I, 2010. http://tel.archives-ouvertes.fr/tel-00740967.
Повний текст джерелаАнотація:
In recent years, Polymer Electrolyte Membrane Fuel Cells (PEMFC) have attracted much attention due to their potential as a clean power source for many applications, including automotive, portable and stationary devices. This resulted in a tremendous technological progress, such as the development of new membranes and electro-catalysts or the improvement of electrode structures. However, in order to compete within the most attractive markets, the PEMFC technologies did not reach all the required characteristics yet, in particular in terms of cost and durability.Because of the strong coupling between different physicochemical phenomena, the interpretation of experimental observations is difficult, and analysis through modeling becomes crucial to elucidate the degradation and failure mechanisms, andto help improving both PEMFC electrochemical performance and durability.The development of a theoretical tool is essential for industrials and the scientific community to evaluate the PEMFC degradation and to predict itsperformance and durability in function of the materials properties and in a diversity of operating conditions. This manuscript summarizes my scientific research efforts in this exciting topic during the last 9 years in France, including my invention of the MEMEPhys multiscale simulation package,developed on the basis of my childhood passion for the New Technologies for Energyin Argentina. My perspectives of adapting this approach to other electrochemical systems such as water electrolyzers and batteries are also discussed.
41
Daun, Kevin. "Impact of energy storage technologies in a distribution grid : An analysis of Key Performance Indicators relating to a local grid’s performance characteristics." Thesis, Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-55367.
Повний текст джерелаАнотація:
The energy system is undergoing a transformation on a never before witnessed scale. The changes are driven by global market forces and technological advancements, improving on a seemingly exponential scale. This in turn has led to the price of both renewables and the accompanying technology decrease over time, making the transition into renewables more economically viable. The drawback of variable renewable energy is that it is variable and dependent on the surrounding environment. Therefore, storing the energy during hours of production, to be used at a later stage when energy demand is higher is becoming ever more important and an attractive option. The purpose of this degree project is to, from a set of performance indicators, evaluate three different energy storage technologies and their respective impact on a distribution grid. The examined storage technologies are: Batteries, Capacitators and a H2 Fuel cell. A literature study was performed in order to find out how grid performance is evaluated, and how the different storage technologies operate. The obtained literature comes from scientific reports, and papers, found by utilizing Mälardalens University library-database. A model representing a Swedish grid with a connection point to the distribution side was created. The model is taken from previous credited work, and customized to fit the operational parameters of a Swedish grid. It was decided that the key indicators for evaluating the state of a grid was to look at the: voltage- and frequency variations, load factor, capacity factor and the overall system efficiency. The simulation is a discrete time simulation that utilizes parameters indicative of one full day of data. The results showed that, from a technological standpoint, the supercapacitor performed better in more categories than the Li-ion battery and H2 fuel cell. However, the Li-ion battery reduced the peaks of the frequency measurements which is a key metric when deciding on grid health. Also, there is the added benefit of the battery and fuel cell of having a longer operational time before the state of charge is depleted. This increases the flexibility of the technology and could therefore be more beneficial in other applications where power supply is more scarce.
42
Brundin, Carl. "Alternative energy concepts for Swedish wastewater treatment plants to meet demands of a sustainable society." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-146831.
Повний текст джерелаАнотація:
This report travels through multiple disciplines to seek innovative and sustainable energy solutions for wastewater treatment plants. The first subject is a report about increased global temperatures and an over-exploitation of natural resources that threatens ecosystems worldwide. The situation is urgent where the current trend is a 2°C increase of global temperatures already in 2040. Furthermore, the energy-land nexus becomes increasingly apparent where the world is going from a dependence on easily accessible fossil resources to renewables limited by land allocation. A direction of the required transition is suggested where all actors of the society must contribute to quickly construct a new carbon-neutral resource and energy system. Wastewater treatment is as required today as it is in the future, but it may move towards a more emphasized role where resource management and energy recovery will be increasingly important. This report is a master’s thesis in energy engineering with an ambition to provide some clues, with a focus on energy, to how wastewater treatment plants can be successfully integrated within the future society. A background check is conducted in the cross section between science, society, politics and wastewater treatment. Above this, a layer of technological insights is applied, from where accessible energy pathways can be identified and evaluated. A not so distant step for wastewater treatment plants would be to absorb surplus renewable electricity and store it in chemical storage mediums, since biogas is already commonly produced and many times also refined to vehicle fuel. Such extra steps could be excellent ways of improving the integration of wastewater treatment plants into the society. New and innovative electric grid-connected energy storage technologies are required when large synchronous electric generators are being replaced by ‘smaller’ wind turbines and solar cells which are intermittent (variable) by nature. A transition of the society requires energy storages, balancing of electric grids, waste-resource utilization, energy efficiency measures etcetera… This interdisciplinary approach aims to identify relevant energy technologies for wastewater treatment plants that could represent decisive steps towards sustainability.
43
Rathore, Akshay Kumar. "High-frequency transformer isolated power conditioning system for fuel cells to utility interface." Thesis, 2008. http://hdl.handle.net/1828/2871.
Повний текст джерелаАнотація:
This thesis presents interfacing of fuel cells to a single-phase utility line using a high-frequency transformer isolated power converter. This research contributes towards selecting a suitable utility interfacing scheme and then designing a power conditioning system along with its control for connecting fuel cells to a single-phase utility line that can achieve high efficiency and compact size. The power conditioning system, designed and built in the research laboratory is connected with the utility line and the experimental results are presented.
Based on the literature available on photovoltaic (PV) array and fuel cell based utility interactive inverters with high-frequency transformer isolation, the interfacing schemes for connecting a DC source, in particular fuel cells, to a single-phase utility line are classified. Based on the fuel cell characteristics and properties, performance and the comparison of these utility interfacing schemes, a suitable scheme for the present application is selected.
Because of low voltage fuel cells, the system takes higher current from the fuel cell and results in lower efficiency of the system. The inverter stage of the selected scheme deals with the higher voltage (lower current) and therefore, its efficiency is higher. In this sense, the efficiency of the whole system depends mainly on the efficiency of the front-end DC-DC converter. To realize a low cost, small size and light weight system, soft-switching is required. Various soft-switched DC-DC converter topologies are compared for the given specifications. Based on the soft-switching range, efficiency and other merits and demerits, a current-fed DC-DC converter configuration is selected. The performance of the selected topology is evaluated for the given specifications. Detailed analysis, a systematic design, simulation and the experimental results of the converter (200 W, operating at 100 kHz) are presented.
To achieve soft-switching for wide variation in input voltage and load while maintaining high efficiency has been a challenge, especially for the low voltage higher input current applications. The variation in pressure/flow of the fuel input to the fuel cells causes the variation in fuel cell stack voltage and the available power supplied to the load/utility line. It causes the converter to enter into hard switching region at higher input voltage and light load. A wide range soft-switched active-clamped current-fed DC-DC converter has been proposed, analyzed and designed and the experimental results (200 W, operating at 100 kHz) are presented.
The fuel-cell voltage varies with fuel pressure and causes the variation in the output voltage produced by the front-end DC-DC converter at the input of the next inverter stage and will affect the inverter operation. Therefore, the front-end DC-DC converter should be controlled to produce a constant voltage at the input of the inverter at varying fuel pressure. Small signal modeling and closed loop control design of the proposed wide range L-L type active-clamped current-fed DC-DC converter has been presented to adjust the duty cycle of the converter switches automatically with any variation in fuel pressure to regulate the output voltage of the converter at a specified constant value.
To convert the DC voltage output of the front-end DC-DC converter into utility AC voltage at line frequency and feeding current into utility line with low THD and high line power factor, an average current controlled inverter is designed. The complete power conditioning unit is connected to the single-phase utility line (208 V RMS, 60 Hz) and experimental results are presented. The system shows stable operation at varying reference power level.
44
Yu, Ching-Chou, and 余景州. "Application of Digital Signal Processor Based Multi-Leg DC-DC Power Converter to Fuel-Cell Power Supply System." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/q6aw5b.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
電機工程系
94
This thesis focuses on the design and implementation of a digital signal processor based multi-leg dc-dc power converter for fuel-cell power supply systems. A multi-leg boost converter is designed in this system to reduce the output current ripple and increase the life time of fuel-cell. According to input and output voltage feedback and current feedback controls, the multi-leg power converter can not only balance the current of each leg, but also provide a steady output voltage to load. Besides, a bi-directional dc-dc power converter is used in this system to charge or discharge the batteries and balance the system power. The redundant power of fuel-cell can be stored in batteries by the power control between fuel-cell and batteries. Battery discharge will occur momentarily to meet the instant need of high system current and thereby raise the response speed when load changes. Fuel-cell can thus be operated in the average power point which fit in with the load. In this thesis, the mathematical models and controller of multi-leg dc-dc power converter are built and used for digital control. Then, a high-performance, low-cost digital signal processor (DSP, TMS320F2812) is used as the control core. The control of power converter and the method of power balance control are accomplished by software so as to reduce the cost. A prototype of 1kW multi-leg dc-dc power converter for fuel-cell is developed. The input voltage range is between 26V and 40V. The output voltage is 40V. Moreover, the experimental data show that the efficiency of the system reaches 93%, and the input current ripple of fuel-cell is less than 5%. Simulation and experimental results are given to justify the analysis.
45
KE, TING-RU, and 柯廷儒. "Application of Graphite Film to Development of Fuel Cell Collector Plate and Power Installation." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/h58dvd.
Повний текст джерелаАнотація:
碩士國立勤益科技大學
冷凍空調與能源系
107
This study developed a lightweight collector plate for long-term stable output, which is fixed into the fuel cell module and combined with circuit design to develop a power installation. The FR-4 Glass/Epoxy was used as substrate of collector plate, and the substrate was coated with a layer of copper as conductive layer by using thermal evaporation process. The copper plated conductive layer was covered with graphene suspension, graphene dispersion, graphene ink and graphene target material as corrosion-resistant layer. The sheet resistance and Tafel electrochemical tests were performed for the collector plate, and then 2cell fuel cell module was assembled for AC impedance spectrum measurement, performance test and stability test. The test results showed that the graphene dispersion can deliver 1.2W in the open 2cell fuel cell module. It has the best performance among the four materials. Afterwards, the fuel cell module is assembled and bonded by using this material and hot pressing technique in the concept of PCB, and the fuel cell module is partially cooled by water chiller and fixture to prevent the MEA from being damaged by high temperature in the course of hot pressing. Finally, it is combined with circuit and small hydrogen storage tank to form a power installation. The maximum power output is 1.4W, the power is successfully supplied to LED lamp, fan and mobile phone.
46
Tsai, Hsin-ting, and 蔡欣庭. "Review of the Impacts on Power Quality and System Stability to Power Systems by New Energy Systems :Wind Power﹐Photovoltaic and Fuel Cell." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/01099639640694189342.
Повний текст джерелаАнотація:
碩士國立中正大學
電機工程所
97
Energy demands from human beings are increasing. Electricity usage is also rising from year to year. Nowadays, most electricity comes from the conversion of fossil and hydro energies. Fossil energy storage is limited on earth and using fossil energies would produce green house effect. Sustainable energy conversion technologies are developing around the globe to replace the dependence on fossil-based generation. New electricity generation technologies, e.g. wind turbine, photovoltaic, fuel cell and etc., are penetrating in the power system network in a great increasing rate. In this thesis, based on published works, we discuss on the power quality problems that may be induced by the integration of these new energy generation systems into power systems. Several mitigation methods to the power quality problems are listed and their operations are discussed. In addition, when new energy generations are integrated into power systems, the impacts of transient stability when fault occurs, or switch-in or switch-off these new energy sources are analyzed. Counter-control methods are also discussed.
47
Huang, Yu-Jr, and 黃昱智. "Application of Sliding-Mode Controller to the DC Power Converter of Fuel Cell Generation Systems." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/uhefb5.
Повний текст джерелаАнотація:
碩士國立臺灣科技大學
電機工程系
95
The purpose of the thesis is to present a method of producing a DC/DC power converter of fuel cell generation systems, with boosting fuel cells low DC voltage to high DC output voltage. The systems must have the capacity of power compensating. Thus, we use a battery bank as an adjusting use of the fuel cell generation systems. Once the loading varies, the systems must have the capacity of robust responses. The systems use a full-bridge DC/DC converter for the fuel cells, and boost/buck DC chopper as the converter of the battery’s charging and discharging. In the thesis, we use a sliding-mode controller as the voltage controller of the DC bus, and the digital signal processor (DSP TMS320F2812) as the control unit, which controlling strategy is accomplished by the C programming. The result shows that, when the full-bridge power converter is joined with boost/buck DC chopper in parallel, it can serve a DC voltage of over 340V and a power of 800W, meanwhile, as output voltage of the fuel cells changes due to loadings, the sliding-mode controller can cause more rapid responses and robustness to the DC bus voltage source.
48
Iglesia, Jericha Cher Rodriguez, and 林雨潔. "Tailoring the Structure and Properties of Cathode to Achieve High-Power Density PEM Fuel Cell." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/c4wdyp.
Повний текст джерелаАнотація:
碩士國立中央大學
能源工程研究所
107
Recently, fuel cell technologies have received much attention as an alternative energy source. Fuel cells are like batteries that convert chemical energy into electricity. Different specifications and system design of the fuel cells are required for different applications. Among all the fuel cells, PEM fuel cell produces the most power for a given volume of the fuel cell, which makes them suitable for vehicles. In this study, pulsed laser deposition (PLD) in Ar atmosphere was used to deposit Pt nanoparticles on the gas diffusion layers (GDLs). There were two methods of tailoring the GLDs have been explored in this study. The first method is to improve the proton transport by drop casting Nafion on the GDL. The second topic is centered on increasing the surface area of the catalyst by laser micro-machining the GDL. On the first method, the influence of Nafion® ionomer content drop casted on the GDL was investigated. The addition of Nafion® ionomer content in the catalyst ink enhances the proton conduction. In our study, Nafion® ionomer content is separately deposited on the GDL. The Pt was first deposited on the GDL and afterwards drop casted by Nafion® solution. Different Nafion® concentrations were diluted in different concentrations of water and ethanol. Results showed that the wettability of the substrate and the solution play a great role in achieving the highest current density. At lower Pt loading, 100 μg cm2, the optimized Nafion®, water, and ethanol concentration were 0.05 wt%, 33.5%, and 66.5%, respectively. On the other hand, at higher Pt loading, 200 μg cm2, the optimized Nafion® concentration was 0.025 wt%. Further characterizations are needed to quantify the drop casting method. The second method include laser micro-machining the substrate. Laser-micromachining the substrate demonstrate that by increasing the Pt loading the power density does not drop. Increasing the Pt loading increases the film thickness which affects the fuel cell performance. Firstly, the picosecond laser fabricates grooves on the surface of the gas diffusion layer to greatly increase the effective surface area of Pt deposition, thereby re- ducing the Pt film thickness. And, secondly, pulsed laser deposition was used to deposit the Pt on to the catalyst. A 2-fold increase in the maximum power density is achieved by using laser micro-machined periodic grooves of 40 μm period, 20 μm groove width, and 10 μm depth, reach 853 mW/cm2 and a maxmimum power density of 1.2 mW/cm−2 with a cathode Pt loading of 200 μg/cm2 . Further promotion is expected if the groove width and the period could be reduced by improving the laser micro-machining process.
49
Gaweł, Duncan Albert Wojciech. "The Development of a Coupled Physics and Kinetics Model to Computationally Predict the Powder to Power Performance of Solid Oxide Fuel Cell Anode Microstructures." Thesis, 2013. http://hdl.handle.net/1974/8399.
Повний текст джерелаАнотація:
A numerical model was developed to evaluate the performance of detailed solid oxide fuel cell (SOFC) anode microstructures obtained from experimental reconstruction techniques or generated from synthetic computational techniques. The model is also capable of identifying the linear triple phase boundary (TPB) reaction sites and evaluating the effective transport within the detailed structures, allowing a comparison between the structural properties and performance to be conducted. To simulate the cell performance, a novel numerical coupling technique was developed in OpenFOAM and validated. The computational grid type and mesh properties were also evaluated to establish appropriate mesh resolutions to employ when studying the performance. The performance of a baseline synthetic electrode structure was evaluated using the model and under the applied conditions it was observed that the ionic potential had the largest influence over the performance.
The model was used in conjunction with a computational synthetic electrode manufacturing algorithm to conduct a numerical powder to power parametric study investigating the effects of the manufacturing properties on the performance. An improvement in the overall performance was observed in structures which maximized the number of reaction sites and had well established transport networks in the ion phase. From the manufacturing parameters studied a performance increase was observed in structures with low porosity and ionic solid volume fractions near the percolation threshold, and when the anodes were manufactured from small monosized particles or binary mixtures comprising of smaller oxygen ion conductive particles. Insight into the anode thickness was also provided and it was observed that the current distribution within the anode was a function of the applied overpotential and an increase in the overpotential resulted in the majority of the current production to increase and shift closer to the electrode-electrolyte interface.Thesis (Master, Mechanical and Materials Engineering) -- Queen's University, 2013-10-01 09:41:47.617
50
Huang, Chien-Yao, and 黃健曜. "Fabrication of Highly Hydrophilic Catalyst Anode by Electrophoretic Deposition to Extend Power Efficiency of PEM Fuel Cells at Low Humidity Conditions." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/71855280866794209684.
Повний текст джерелаАнотація:
碩士逢甲大學
綠色能源科技碩士學位學程
101
The aim of this study is to fabricate membrane electrode assembly (MEA) by using novel hydrophilic catalysts including platinum nanocatalysts with silica nanospheres (Pt/C-SiO2), platinum nanocatalysts with hollow silica nanospheres (Pt/C-hSiO2), pyrolytically synthesized platinum particles mixed with activated carbon and hollow silica nanospheres (Pt/C/hSiO2). The modified catalyst layer with enhanced hydrophilicity was prepared by electrophoresis deposition (EPD) method. Effect of hydrophilic material in the catalyst layer on improvement of proton exchange membrane fuel cell (PEMFC) operating life under low humidity conditions was investigated. The Pt/C nanocatalysts were also deposited on carbon paper (SGL-10BC) to be gas diffusion electrodes (GDE) of PEMFC by EPD process. A uniform Pt/C layer, which was obtained under EPD’s electrical field of 280 V/cm, was of 420 mA/cm2 current density under I-V test at 0.6 V. The hydrophilic GDE (Pt/C-SiO2, Pt/C-hSiO2) under the I-V test showed the optimal content for SiO2 and hSiO2 for the best performance were 33wt% and 16wt%, respectively., Such hydrophilic GDE does improve MEA’s humidification ability and cell operating stability, which showed its cell voltage decade at 4.52~6.77% through 560 hr continuous operation at the low-humidity conditions, as compared cell voltage decade of normal GDE more than 15.5%. For hydrophilic multilayered Pt/C/hSiO2 composite, where the Pt/C catalyst (size of Pt particles range from 8.17 to 10.02 nm) were produced from one-step and two-step thermally reduced processes, had current density of 42 mA/cm2 from I-V test. When silica templates in Pt/C/hSiO2 composite were removed by HF solution, the triple phase boundaries (TPB) of MEA was boosted and the current density was substantially increased (63 mA/cm2 in ohmic polarization region and 238 mA/cm2 in concentration polarization region) due to the enhanced transfer efficiency of the fuel gases as well as conduction velocity of water molecules.